# Beam instability studies at the APS

## Abstract

The Argonne Advanced Photon Source, APS (Fig. 1), is a 7-GeV positron storage ring with a circumference of 1104 m. It has a ``third generation, DBA or Chasman-Green`` lattice composed of 40 sectors each having a {approximately}6 m long zero-dispersion straight-section for accommodating insertion devices. Neighboring straight-sections are connected by a 360{degrees}/40 = 9{degrees} double-bend-achromatic bending section designed to produce the smallest emittance attainable with reasonable component parameter values and dynamic apertures. Thus, it is a very strongly focusing lattice with v{sub x} = 35.22 and v{sub y} = 14.30. The beam chamber of the storage ring including all rf, vacuum and photon beam components is designed to ensure that a beam current > 100 mA can be stably stored. We expect that the maximum stable beam current could be as high as 300 mA. This paper will give some details of the studies and computations to ensure the stability of such a beam. The discussions will be organized in the following three parts: Coupled-bunch instability caused by the higher-order modes (HOMs) of the rf cavities; Single-bunch instability due to the resistive wall impedance; and Single-bunch instability due to broadband impedances arising from beam chamber irregularities.

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab., IL (United States)

- Sponsoring Org.:
- USDOE, Washington, DC (United States)

- OSTI Identifier:
- 10189198

- Report Number(s):
- ANL/ASD/CP-84183; CONF-9407121-3

ON: DE95001448; TRN: 94:021170

- DOE Contract Number:
- W-31109-ENG-38

- Resource Type:
- Conference

- Resource Relation:
- Conference: Workshop on beam instabilities in storage rings,Hefei (China),25-30 Jul 1994; Other Information: PBD: [1994]

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; BEAM DYNAMICS; INSTABILITY; ADVANCED PHOTON SOURCE; BEAM BUNCHING; IMPEDANCE; 430200; BEAM DYNAMICS, FIELD CALCULATIONS, AND ION OPTICS

### Citation Formats

```
Teng, L C.
```*Beam instability studies at the APS*. United States: N. p., 1994.
Web.

```
Teng, L C.
```*Beam instability studies at the APS*. United States.

```
Teng, L C. Sat .
"Beam instability studies at the APS". United States. https://www.osti.gov/servlets/purl/10189198.
```

```
@article{osti_10189198,
```

title = {Beam instability studies at the APS},

author = {Teng, L C},

abstractNote = {The Argonne Advanced Photon Source, APS (Fig. 1), is a 7-GeV positron storage ring with a circumference of 1104 m. It has a ``third generation, DBA or Chasman-Green`` lattice composed of 40 sectors each having a {approximately}6 m long zero-dispersion straight-section for accommodating insertion devices. Neighboring straight-sections are connected by a 360{degrees}/40 = 9{degrees} double-bend-achromatic bending section designed to produce the smallest emittance attainable with reasonable component parameter values and dynamic apertures. Thus, it is a very strongly focusing lattice with v{sub x} = 35.22 and v{sub y} = 14.30. The beam chamber of the storage ring including all rf, vacuum and photon beam components is designed to ensure that a beam current > 100 mA can be stably stored. We expect that the maximum stable beam current could be as high as 300 mA. This paper will give some details of the studies and computations to ensure the stability of such a beam. The discussions will be organized in the following three parts: Coupled-bunch instability caused by the higher-order modes (HOMs) of the rf cavities; Single-bunch instability due to the resistive wall impedance; and Single-bunch instability due to broadband impedances arising from beam chamber irregularities.},

doi = {},

url = {https://www.osti.gov/biblio/10189198},
journal = {},

number = ,

volume = ,

place = {United States},

year = {1994},

month = {10}

}